docs: def precision(Ntp, Nsys, eps=numpy.spacing(1)):
      """Precision.
  
      Wikipedia entry https://en.wikipedia.org/wiki/Precision_and_recall
  
      Parameters
      ----------
      Ntp : int >=0
          Number of true positives.
  
      Nsys : int >=0
          Amount of system output.
  
      eps : float
          eps.
          Default value numpy.spacing(1)
  
      Returns
      -------
      precision: float
          Precision
  
      """
  
      if Nsys == 0:
          return numpy.nan
      else:
          return float(Ntp / float(Nsys))